CODEWITHSUNDEEP
c++
Al-ameen Adediran
Al-ameen Adediran

Reputation: 1

Editing sstreams in C++

#include <vector>
#include <string>
#include <sstream>
#include <iostream>

int main()
{
    std::string str = "1,2,3,4,5,6";
    std::vector<int> vect;

    std::stringstream ss(str);

    for (int i=1; ss >> i;) {
        vect.push_back(i);
        if (ss.peek() == ',')
            ss.ignore();
    }

    for (std::size_t i = 0; i < vect.size(); i++)
        std::cout << vect[i] << std::endl;

}

I have this code. I'm trying to remove the first and last values from the string. I have tried deleting those values before getting to the for loop but it doesn't work.

Upvotes: 0

Views: 142

Answers (2)

Ted Lyngmo
Ted Lyngmo

Reputation: 117851

Here's an alternative to messing with the actual stringstream. Extract the ints and remove the first and last from the resulting vector.

#include <vector>
#include <string>
#include <sstream>
#include <iostream>
#include <iterator>

int main() {
    std::string str = "1,2,3,4,5,6";

    std::stringstream ss(str);
    std::vector<int> vect;

    while(ss) {                    // is the stream in a good state
        if(int v; ss >> v) {       // try to extract an int
            vect.push_back(v);     // success, save it
        } else if(not ss.eof()) {  // check that the stream is not depleated
            ss.clear();            // clear the failstate
            ss.ignore();           // ignore 1 char
        } // else leave the stream in a failed state to exit the while loop
    }

    // erase the last int in the vector
    if(not vect.empty()) vect.erase(std::prev(vect.end()));

    // erase the first int in the vector
    if(not vect.empty()) vect.erase(vect.begin());

    for (int val : vect)
        std::cout << val << '\n';

}

Upvotes: 2

asmmo
asmmo

Reputation: 7100

To remove the last and first characters from the string

str = str.substr(1, str.size() - 2);

Or

str.erase(str.begin());
str.erase(--str.end());

To remove the two last and two first characters from the string

str = str.substr(2, str.size() - 4);

Or

    str.erase(str.begin(), str.begin()+2);
    str.erase(str.end()-2, str.end());

Upvotes: 2

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